JDAOEBCMXFMZNCTKKAKDNZC→
looks up bob@bobsemail.com
“How do I invert the function?”

“Oh, look, it’s a message.”
bob@bobsemail.com↓
makes decryption key D

JDAOEBCMXFMZNCTKKAKDNZC
↓ D
“Hi, Bob, this is Alice.”

How can Alice send Bob a secret message before Bob even knows he needs a secret key???

We are going to be using facts about integers to do some cool things in cryptography, like Identity-Based Encryption. You don’t have to know anything about cryptography to start, but if you do I think you will still learn something new!

Requirements

The prerequisite for this class is DISCO I (Math 275) or Number Theory (Math 378). (Banner says Math 375 but I will waive that if you have had Math 275.) If you have had some other experience with number theory or cryptography, come see me and we’ll talk.